Grinding or polishing machine



No. 623,742. Patented Apr. 25, I899. E. RIVETT.

GRINDING 0R POLISHING MACHINE.

(Application flied Aug. 12, 1897.)

'(No Model.) 2 Sheets-Sheet l.

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Patented Apr. 25, I899.

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E. RIVETT.

GRINDING 0R POLISHING MACHINE.

(Application filed Aug. 12, 1897.)

(No Model.)

NlTE rates EDVARD RIVETT, OF BOSTON, MASSACHUSETTS.

GRINDING OR POLISHING MACHINE.

SPECIFICATION forming part of Letters Patent No. 623,742, dated April25, 1899.

Application filed August 12, 1897. Serial No. 647,743. (No model.)

To all whom, it may concern.-

Be it known that I, EDWARD RIVETT, of Boston, county of Suffolk, andState of Massachusetts,have invented an Improvement in Grinding orPolishing Machines, of which the following description, in connectionwith the accompanying drawings, is a specification, like letters andnumerals on the drawings representing like parts.

This invention relates to grinding and polishing machines having a heador spindle carrying the object to be ground or polished and a grindingor polishing tool; 'and it has for its object to improve theconstruction of the means employed for reciprocating one of saidessential parts of the machine relative to the other-as, for instance,to reciprocate the head or spindle relative to the grinding or polishingtooland for adjusting the reciprocating device in such manner as to varythe length of travel or extent of reciprocating movement of said head.

In carrying out this invention the reciprorotated, and it is madetapering from end to v end, thereby giving to it a varying radius, andmeans are provided for adjusting it along on said shaft, so that anypart of it may be brought into position to act upon the engaging portionof the head to thereby reciprocate said head to a greater or lessextent, and consequently vary the limits of movement in each direction.

Figure 1 shows in side elevation a longitudinal vertical section of agrinding and polishing machine embodying this invention; Fig. 2, avertical section of the machine shown in Fig. 1, taken on the dottedline a: 00.

The main frame Ais of suitable shape and construction to support theoperating parts.

(t represents a frame or head mounted on the frame A and adapted toslide thereon transversely, it having a depending lug or ear a, whichpasses through a slot in the frame A and which is engaged by ascrew-threaded rod a having a handpiece a by which it may be turned,said rod 6Z2 turning in the frame A and serving as an adjusting devicefor the head a. The head a has its upper end formed or provided with ahorizontal bearing or support, which is adapted to receive within it ashaft Z) and bushings at the ends of said shaft 1).

Each end of the shaftb' is provided with a belt-pulley b and adriving-shaft c has its bearings in the head a, which has secured to it,at a point substantially midway its length, a driving-pulley c, and ithas also secured to it at its ends driving-pulleys 0 0 which receivebelts 20, which pass around the pulleys b on the shaft 1). The shaft bis constructed and arranged to serve as a shaft to carry the grindingand polishing tool, and any suitable form or construction of tool maybeemployed, as an emery-wheel.

The spindle (Z has its bearings in a head (1, and it has secured to itsuitable belt-pulleys 01 and said spindle is constructed and arranged toreceive and support the part to be ground or polished, and said head dis mounted upon the frame A and, as herein shown, is adapted to bereciprocated longitudinally or toward and from the grinding andpolishing tool.

The head d is provided on its under side with a dovetailed recess,whichreceives a dove tailed projection d formed or provided on a slide 61constructed and arranged to slide back and forth in a slot provided forit in the frame A, and said slide (1 has depending from it a yoke (1which surrounds or incloses a cam e, secured to or mounted upon a shaft6,

said yoke having a f riction-roll d or an equivalent engaging portion,which is in continuous engagement with said cam e. The journals of thefriction-roll d are rotatably mounted in an upright support 61 Fig.l,which is journaled in lateral ears d ,-secured to or forming part ofthe yoke d whereby the support is adapted to rock on substantiallyvertical pivots, so that the face of the roll will remain in parallelismand in contact with the surface of the cam e whatever portion of thelatter is adjusted to rotate opposite said roll. The yoke has projectingfrom it, in opposite ways, horizontal rods or bars 61 (1 which slide inbearings for them in the main frame A, and a strong spring 61 isattached at one end to the frame and at the other end to said yoke,

9 Beam which serves as a means for continuously holding the yoke inengagement with the cam.

The cam e is made heart-shaped in crosssection and tapering from end toend, and it is mounted upon a hollow shaft e, and it has secured to itasat one end, for instancea projection 6 which enters a slot formed orprovided in said shaft c, said projection having a screw-threaded holethrough it which receives the screw-threaded end 6 of a rod which passesaxially through the shaft 6, said rod having an end piece or hand-wheele, by means of which it may be turned. As said rod, with itsscrew-threaded end a is turned the tapering heart-shaped cam 6 will beadjusted longitudinally along on the shaft e, upon which it is mounted,and the roll (1 on the yoke will engage it at different points,according to the relative positions of said cam and yoke.

The shaft c has secured to its rear end a beveled gear f, which isengaged by a beveled gear f, which may be turned by any power-drivenshaft to in turn rotate the camshaft 6'.

It will be seen that as the camshaft 6' revolves the cam 6 will becorrespondingly turned, and by its engagement with the yoke dependingfrom the head (1 or other engaging portion said head will be moved at aconstant speed toward and from the tool-carrying shaft 1) and that asthe cam is adjusted along on the shaft supporting it the stroke orextent of movement of said head may be variedthat is to say, it may bemore or less.

The head (1' is connected with or locked to the slide (1 by a set-screw30, so that said head may be connected to said slide at different pointsand may be quickly disconnected at any time to be moved independently ofthe slide to test the work or for any other purpose.

In order to effect a uniform reciprocation of the moving part aifeetedby the cam, the latter must be of a true heart shape in crosssection andmade tapering from end to end, so that any cross-section of the cam willbe of similar shape to any other, and unless the cam is trulyheart-shaped, as in the present case, the periods of reversal of thepart to be reciprocated will be indefinite and irregular.

I claim 1. Inagrindingorpolishingmachine,atoolcarrying shaft, awork-holding spindle, and means for reciprocating one of said partsrelatively to the other, said means comprising a rotatable heart-shapedcam made tapering from end to end, and an engaging member mounted torock on the reciprocating part to thereby continuously bear upon oragainst said cam and in parallelism with its surface.

2. The revolving heart-shaped cam made tapering from end to end,combined with a part to be reeiprocated, a roll thereon in continuousengagement with the surface of the cam, and means for adjusting said camand the part to be reciprocated one relatively to the other in thedirection of the longitudinal axis of the cam to vary the extent ofrecipro eating movement, substantially as described;

3. In a grinding orpolishing machine, alongitudinally-slotted mainframe, a slide movable thereon, a tool-shaft, a work-holding spindle,one of said parts being movable with the slide, a yoke depending fromthe latter and provided with bars extended in the direction of travelofthe slide, bearingsin which said bars move and are supported, arotatable tapering heart cam mounted in and at right angles to the yoke,means to adjust the position of said cam, a roll on the yoke, mounted torock in upright pivots thereon to thereby be maintained continuously inengagement with the cam-surface, and a spring to maintain the roll andone side of the yoke pressed toward the cam, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

EDW'ARD RIVETT.

' \Vitnesses:

B. J. Noyes, ARTHUR F. RANDALL.

